1 <?xml version="1.0" encoding="ISO-8859-1"?>
2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
3 <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!--
4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
5 This file is generated from xml source: DO NOT EDIT
6 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
8 <title>Mapping URLs to Filesystem Locations - Apache HTTP Server</title>
9 <link href="./style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
10 <link href="./style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
11 <link href="./style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" />
12 <link href="./images/favicon.ico" rel="shortcut icon" /></head>
13 <body id="manual-page"><div id="page-header">
14 <p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="./faq/">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p>
15 <p class="apache">Apache HTTP Server Version 2.3</p>
16 <img alt="" src="./images/feather.gif" /></div>
17 <div class="up"><a href="./"><img title="<-" alt="<-" src="./images/left.gif" /></a></div>
19 <a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="./">Version 2.3</a></div><div id="page-content"><div id="preamble"><h1>Mapping URLs to Filesystem Locations</h1>
21 <p><span>Available Languages: </span><a href="./en/urlmapping.html" title="English"> en </a> |
22 <a href="./fr/urlmapping.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
23 <a href="./ja/urlmapping.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
24 <a href="./ko/urlmapping.html" hreflang="ko" rel="alternate" title="Korean"> ko </a> |
25 <a href="./tr/urlmapping.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
28 <p>This document explains how the Apache HTTP Server uses the URL of a request
29 to determine the filesystem location from which to serve a
32 <div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#related">Related Modules and Directives</a></li>
33 <li><img alt="" src="./images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
34 <li><img alt="" src="./images/down.gif" /> <a href="#outside">Files Outside the DocumentRoot</a></li>
35 <li><img alt="" src="./images/down.gif" /> <a href="#user">User Directories</a></li>
36 <li><img alt="" src="./images/down.gif" /> <a href="#redirect">URL Redirection</a></li>
37 <li><img alt="" src="./images/down.gif" /> <a href="#proxy">Reverse Proxy</a></li>
38 <li><img alt="" src="./images/down.gif" /> <a href="#rewrite">Rewriting Engine</a></li>
39 <li><img alt="" src="./images/down.gif" /> <a href="#notfound">File Not Found</a></li>
40 <li><img alt="" src="./images/down.gif" /> <a href="#other">Other URL Mapping Modules</a></li>
42 <div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
44 <h2><a name="related" id="related">Related Modules and Directives</a></h2>
46 <table class="related"><tr><th>Related Modules</th><th>Related Directives</th></tr><tr><td><ul><li><code class="module"><a href="./mod/mod_actions.html">mod_actions</a></code></li><li><code class="module"><a href="./mod/mod_alias.html">mod_alias</a></code></li><li><code class="module"><a href="./mod/mod_dir.html">mod_dir</a></code></li><li><code class="module"><a href="./mod/mod_imagemap.html">mod_imagemap</a></code></li><li><code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code></li><li><code class="module"><a href="./mod/mod_proxy.html">mod_proxy</a></code></li><li><code class="module"><a href="./mod/mod_rewrite.html">mod_rewrite</a></code></li><li><code class="module"><a href="./mod/mod_speling.html">mod_speling</a></code></li><li><code class="module"><a href="./mod/mod_userdir.html">mod_userdir</a></code></li><li><code class="module"><a href="./mod/mod_vhost_alias.html">mod_vhost_alias</a></code></li></ul></td><td><ul><li><code class="directive"><a href="./mod/mod_alias.html#alias">Alias</a></code></li><li><code class="directive"><a href="./mod/mod_alias.html#aliasmatch">AliasMatch</a></code></li><li><code class="directive"><a href="./mod/mod_speling.html#checkspelling">CheckSpelling</a></code></li><li><code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code></li><li><code class="directive"><a href="./mod/core.html#errordocument">ErrorDocument</a></code></li><li><code class="directive"><a href="./mod/core.html#options">Options</a></code></li><li><code class="directive"><a href="./mod/mod_proxy.html#proxypass">ProxyPass</a></code></li><li><code class="directive"><a href="./mod/mod_proxy.html#proxypassreverse">ProxyPassReverse</a></code></li><li><code class="directive"><a href="./mod/mod_proxy.html#proxypassreversecookiedomain">ProxyPassReverseCookieDomain</a></code></li><li><code class="directive"><a href="./mod/mod_proxy.html#proxypassreversecookiepath">ProxyPassReverseCookiePath</a></code></li><li><code class="directive"><a href="./mod/mod_alias.html#redirect">Redirect</a></code></li><li><code class="directive"><a href="./mod/mod_alias.html#redirectmatch">RedirectMatch</a></code></li><li><code class="directive"><a href="./mod/mod_rewrite.html#rewritecond">RewriteCond</a></code></li><li><code class="directive"><a href="./mod/mod_rewrite.html#rewriterule">RewriteRule</a></code></li><li><code class="directive"><a href="./mod/mod_alias.html#scriptalias">ScriptAlias</a></code></li><li><code class="directive"><a href="./mod/mod_alias.html#scriptaliasmatch">ScriptAliasMatch</a></code></li><li><code class="directive"><a href="./mod/mod_userdir.html#userdir">UserDir</a></code></li></ul></td></tr></table>
47 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
49 <h2><a name="documentroot" id="documentroot">DocumentRoot</a></h2>
51 <p>In deciding what file to serve for a given request, httpd's
52 default behavior is to take the URL-Path for the request (the part
53 of the URL following the hostname and port) and add it to the end
54 of the <code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code> specified
55 in your configuration files. Therefore, the files and directories
56 underneath the <code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code>
57 make up the basic document tree which will be visible from the
60 <p>For example, if <code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code>
61 were set to <code>/var/www/html</code> then a request for
62 <code>http://www.example.com/fish/guppies.html</code> would result
63 in the file <code>/var/www/html/fish/guppies.html</code> being
64 served to the requesting client.</p>
66 <p>httpd is also capable of <a href="vhosts/">Virtual
67 Hosting</a>, where the server receives requests for more than one
68 host. In this case, a different <code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code> can be specified for each
69 virtual host, or alternatively, the directives provided by the
70 module <code class="module"><a href="./mod/mod_vhost_alias.html">mod_vhost_alias</a></code> can
71 be used to dynamically determine the appropriate place from which
72 to serve content based on the requested IP address or
75 <p>The <code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code> directive
76 is set in your main server configuration file
77 (<code>httpd.conf</code>) and, possibly, once per additional <a href="vhosts/">Virtual Host</a> you create.</p>
78 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
80 <h2><a name="outside" id="outside">Files Outside the DocumentRoot</a></h2>
82 <p>There are frequently circumstances where it is necessary to
83 allow web access to parts of the filesystem that are not strictly
84 underneath the <code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code>. httpd offers several
85 different ways to accomplish this. On Unix systems, symbolic links
86 can bring other parts of the filesystem under the <code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code>. For security reasons,
87 httpd will follow symbolic links only if the <code class="directive"><a href="./mod/core.html#options">Options</a></code> setting for the relevant
88 directory includes <code>FollowSymLinks</code> or
89 <code>SymLinksIfOwnerMatch</code>.</p>
91 <p>Alternatively, the <code class="directive"><a href="./mod/mod_alias.html#alias">Alias</a></code> directive will map any part
92 of the filesystem into the web space. For example, with</p>
94 <div class="example"><p><code>Alias /docs /var/web</code></p></div>
96 <p>the URL <code>http://www.example.com/docs/dir/file.html</code>
97 will be served from <code>/var/web/dir/file.html</code>. The
98 <code class="directive"><a href="./mod/mod_alias.html#scriptalias">ScriptAlias</a></code> directive
99 works the same way, with the additional effect that all content
100 located at the target path is treated as <a class="glossarylink" href="./glossary.html#cgi" title="see glossary">CGI</a> scripts.</p>
102 <p>For situations where you require additional flexibility, you
103 can use the <code class="directive"><a href="./mod/mod_alias.html#aliasmatch">AliasMatch</a></code>
104 and <code class="directive"><a href="./mod/mod_alias.html#scriptaliasmatch">ScriptAliasMatch</a></code>
105 directives to do powerful <a class="glossarylink" href="./glossary.html#regex" title="see glossary">regular
106 expression</a> based matching and substitution. For
109 <div class="example"><p><code>ScriptAliasMatch ^/~([a-zA-Z0-9]+)/cgi-bin/(.+)
110 /home/$1/cgi-bin/$2</code></p></div>
112 <p>will map a request to
113 <code>http://example.com/~user/cgi-bin/script.cgi</code> to the
114 path <code>/home/user/cgi-bin/script.cgi</code> and will treat
115 the resulting file as a CGI script.</p>
116 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
117 <div class="section">
118 <h2><a name="user" id="user">User Directories</a></h2>
120 <p>Traditionally on Unix systems, the home directory of a
121 particular <em>user</em> can be referred to as
122 <code>~user/</code>. The module <code class="module"><a href="./mod/mod_userdir.html">mod_userdir</a></code>
123 extends this idea to the web by allowing files under each user's
124 home directory to be accessed using URLs such as the
127 <div class="example"><p><code>http://www.example.com/~user/file.html</code></p></div>
129 <p>For security reasons, it is inappropriate to give direct
130 access to a user's home directory from the web. Therefore, the
131 <code class="directive"><a href="./mod/mod_userdir.html#userdir">UserDir</a></code> directive
132 specifies a directory underneath the user's home directory
133 where web files are located. Using the default setting of
134 <code>Userdir public_html</code>, the above URL maps to a file
136 <code>/home/user/public_html/file.html</code> where
137 <code>/home/user/</code> is the user's home directory as
138 specified in <code>/etc/passwd</code>.</p>
140 <p>There are also several other forms of the
141 <code>Userdir</code> directive which you can use on systems
142 where <code>/etc/passwd</code> does not contain the location of
143 the home directory.</p>
145 <p>Some people find the "~" symbol (which is often encoded on the
146 web as <code>%7e</code>) to be awkward and prefer to use an
147 alternate string to represent user directories. This functionality
148 is not supported by mod_userdir. However, if users' home
149 directories are structured in a regular way, then it is possible
150 to use the <code class="directive"><a href="./mod/mod_alias.html#aliasmatch">AliasMatch</a></code>
151 directive to achieve the desired effect. For example, to make
152 <code>http://www.example.com/upages/user/file.html</code> map to
153 <code>/home/user/public_html/file.html</code>, use the following
154 <code>AliasMatch</code> directive:</p>
156 <div class="example"><p><code>AliasMatch ^/upages/([a-zA-Z0-9]+)/?(.*)
157 /home/$1/public_html/$2</code></p></div>
158 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
159 <div class="section">
160 <h2><a name="redirect" id="redirect">URL Redirection</a></h2>
162 <p>The configuration directives discussed in the above sections
163 tell httpd to get content from a specific place in the filesystem
164 and return it to the client. Sometimes, it is desirable instead to
165 inform the client that the requested content is located at a
166 different URL, and instruct the client to make a new request with
167 the new URL. This is called <em>redirection</em> and is
168 implemented by the <code class="directive"><a href="./mod/mod_alias.html#redirect">Redirect</a></code> directive. For example, if
169 the contents of the directory <code>/foo/</code> under the
170 <code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code> are moved
171 to the new directory <code>/bar/</code>, you can instruct clients
172 to request the content at the new location as follows:</p>
174 <div class="example"><p><code>Redirect permanent /foo/
175 http://www.example.com/bar/</code></p></div>
177 <p>This will redirect any URL-Path starting in
178 <code>/foo/</code> to the same URL path on the
179 <code>www.example.com</code> server with <code>/bar/</code>
180 substituted for <code>/foo/</code>. You can redirect clients to
181 any server, not only the origin server.</p>
183 <p>httpd also provides a <code class="directive"><a href="./mod/mod_alias.html#redirectmatch">RedirectMatch</a></code> directive for more
184 complicated rewriting problems. For example, to redirect requests
185 for the site home page to a different site, but leave all other
186 requests alone, use the following configuration:</p>
188 <div class="example"><p><code>RedirectMatch permanent ^/$
189 http://www.example.com/startpage.html</code></p></div>
191 <p>Alternatively, to temporarily redirect all pages on one site
192 to a particular page on another site, use the following:</p>
194 <div class="example"><p><code>RedirectMatch temp .*
195 http://othersite.example.com/startpage.html</code></p></div>
196 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
197 <div class="section">
198 <h2><a name="proxy" id="proxy">Reverse Proxy</a></h2>
200 <p>httpd also allows you to bring remote documents into the URL space
201 of the local server. This technique is called <em>reverse
202 proxying</em> because the web server acts like a proxy server by
203 fetching the documents from a remote server and returning them to the
204 client. It is different from normal (forward) proxying because, to the client,
205 it appears the documents originate at the reverse proxy server.</p>
207 <p>In the following example, when clients request documents under the
208 <code>/foo/</code> directory, the server fetches those documents from
209 the <code>/bar/</code> directory on <code>internal.example.com</code>
210 and returns them to the client as if they were from the local
213 <div class="example"><p><code>
214 ProxyPass /foo/ http://internal.example.com/bar/<br />
215 ProxyPassReverse /foo/ http://internal.example.com/bar/<br />
216 ProxyPassReverseCookieDomain internal.example.com public.example.com<br />
217 ProxyPassReverseCookiePath /foo/ /bar/
220 <p>The <code class="directive"><a href="./mod/mod_proxy.html#proxypass">ProxyPass</a></code> configures
221 the server to fetch the appropriate documents, while the
222 <code class="directive"><a href="./mod/mod_proxy.html#proxypassreverse">ProxyPassReverse</a></code>
223 directive rewrites redirects originating at
224 <code>internal.example.com</code> so that they target the appropriate
225 directory on the local server. Similarly, the
226 <code class="directive"><a href="./mod/mod_proxy.html#proxypassreversecookiedomain">ProxyPassReverseCookieDomain</a></code>
227 and <code class="directive"><a href="./mod/mod_proxy.html#proxypassreversecookiepath">ProxyPassReverseCookiePath</a></code>
228 rewrite cookies set by the backend server.</p>
229 <p>It is important to note, however, that
230 links inside the documents will not be rewritten. So any absolute
231 links on <code>internal.example.com</code> will result in the client
232 breaking out of the proxy server and requesting directly from
233 <code>internal.example.com</code>. You can modify these links (and other
234 content) in a page as it is being served to the client using
235 <code class="module"><a href="./mod/mod_substitute.html">mod_substitute</a></code>.</p>
237 <div class="example"><p><code>
238 Substitute s/internal\.example\.com/www.example.com/i
241 <p>Additionally, a third-party module,
242 <a href="http://apache.webthing.com/mod_proxy_html/">mod_proxy_html</a>,
243 is available to rewrite links in HTML and XHTML.</p>
244 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
245 <div class="section">
246 <h2><a name="rewrite" id="rewrite">Rewriting Engine</a></h2>
248 <p>When even more powerful substitution is required, the rewriting
249 engine provided by <code class="module"><a href="./mod/mod_rewrite.html">mod_rewrite</a></code>
250 can be useful. The directives provided by this module can use
251 characteristics of the request such as browser type or source IP
252 address in deciding from where to serve content. In addition,
253 mod_rewrite can use external database files or programs to
254 determine how to handle a request. The rewriting engine is capable
255 of performing all three types of mappings discussed above:
256 internal redirects (aliases), external redirects, and proxying.
257 Many practical examples employing mod_rewrite are discussed in the
258 <a href="rewrite/">detailed mod_rewrite documentation</a>.</p>
259 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
260 <div class="section">
261 <h2><a name="notfound" id="notfound">File Not Found</a></h2>
263 <p>Inevitably, URLs will be requested for which no matching
264 file can be found in the filesystem. This can happen for
265 several reasons. In some cases, it can be a result of moving
266 documents from one location to another. In this case, it is
267 best to use <a href="#redirect">URL redirection</a> to inform
268 clients of the new location of the resource. In this way, you
269 can assure that old bookmarks and links will continue to work,
270 even though the resource is at a new location.</p>
272 <p>Another common cause of "File Not Found" errors is
273 accidental mistyping of URLs, either directly in the browser,
274 or in HTML links. httpd provides the module
275 <code class="module"><a href="./mod/mod_speling.html">mod_speling</a></code> (sic) to help with
276 this problem. When this module is activated, it will intercept
277 "File Not Found" errors and look for a resource with a similar
278 filename. If one such file is found, mod_speling will send an
279 HTTP redirect to the client informing it of the correct
280 location. If several "close" files are found, a list of
281 available alternatives will be presented to the client.</p>
283 <p>An especially useful feature of mod_speling, is that it will
284 compare filenames without respect to case. This can help
285 systems where users are unaware of the case-sensitive nature of
286 URLs and the unix filesystem. But using mod_speling for
287 anything more than the occasional URL correction can place
288 additional load on the server, since each "incorrect" request
289 is followed by a URL redirection and a new request from the
292 <p>If all attempts to locate the content fail, httpd returns
293 an error page with HTTP status code 404 (file not found). The
294 appearance of this page is controlled with the
295 <code class="directive"><a href="./mod/core.html#errordocument">ErrorDocument</a></code> directive
296 and can be customized in a flexible manner as discussed in the
297 <a href="custom-error.html">Custom error responses</a>
299 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
300 <div class="section">
301 <h2><a name="other" id="other">Other URL Mapping Modules</a></h2>
305 <p>Other modules available for URL mapping include:</p>
308 <li><code class="module"><a href="./mod/mod_actions.html">mod_actions</a></code> - Maps a request to a CGI script
309 based on the request method, or resource MIME type.</li>
310 <li><code class="module"><a href="./mod/mod_dir.html">mod_dir</a></code> - Provides basic mapping of a trailing
311 slash into an index file such as <code>index.html</code>.</li>
312 <li><code class="module"><a href="./mod/mod_imagemap.html">mod_imagemap</a></code> - Maps a request to a URL based
313 on where a user clicks on an image embedded in a HTML document.</li>
314 <li><code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code> - Selects an appropriate
315 document based on client preferences such as language or content
320 <div class="bottomlang">
321 <p><span>Available Languages: </span><a href="./en/urlmapping.html" title="English"> en </a> |
322 <a href="./fr/urlmapping.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
323 <a href="./ja/urlmapping.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
324 <a href="./ko/urlmapping.html" hreflang="ko" rel="alternate" title="Korean"> ko </a> |
325 <a href="./tr/urlmapping.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
326 </div><div id="footer">
327 <p class="apache">Copyright 2010 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
328 <p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="./faq/">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p></div>
projects / apache / blob